1. Field of the Invention
The invention relates to 2-R-N-[(trichloromethyl)thio]succinimides represented by the structural formula ##STR1## where R is alkenyl having from 8 to 12 carbon atoms, useful as fungicidal agents, to compositions containing them, and to methods for their use.
2. Description of the Prior Art
Fungicides find application as plant protectants, for the preservation of wood, leather, lacquer, textiles, paper and other organic materials, and in combating fungus infections in animals and man. Many of these fungicides, however, have certain disadvantages. Thus, organic mercury compounds are toxic, organic tin compounds are light sensitive, chlorophenols like pentachlorophenol are volatile and toxic to man, while derivatives of dithiocarbamic acids react with metal siccatives to darken lacquers.
The trichloromethylthio compounds described in U.S. Pat. No. 2,553,770 are good, long acting fungicides whose action is due to the blocking of SH-groups in phosphorylating enzymes, cf. R. G. Owens and H. M. Novotny, Contr. Boyce Thompson Inst., vol. 20, p. 171 (1959). These fungicides are prepared by the reaction of the appropriate dicarboxylic acid imide with trichloromethanesulfenyl chloride. The imides employed as starting materials in this reaction are endomethylene-tetrahydrophthalimide, phthalimide, tetrahydrophthalimide and succinimide. Of the compounds prepared in this manner, primarily compounds represented by the formulas II to IV below are encountered as items of trade. ##STR2##
In addition, fluorinated compounds having formulas V and VI below have been developed: ##STR3##
The properties of the foregoing identified trichloromethylthio compounds in practical use have been reported in "Fette, Seifen, Anstrichmittel", vol. 68, (1966) pp. 275-279 and B. A. Richardson, B.W.P.A. Annual Convention (1972), chapter (6), sapstain control, p. 9. The fungicidal effect of these known agents towards wood- and paint-damaging fungi depends largely on their solubility in petroleum hydrocarbons. Thus, Captan, a good acting fungicide for plant protection, is ineffective against wood- and paint-damaging fungi, owing to its low solubility in petroleum solvents, see B. A. Richardson, loc. cit. The compound IV, obtained from hexahydrophthalimide, is only 0.3% soluble in mineral spirits. Such a low solubility is for most purposes insufficient.
Recently, an important factor in evaluating fungicides has been their harmlessness to man. Certain trichloromethylthio compounds, such as Capstan (II) and Folpet (III), recently have become suspect as producing malformation-causing mutations, cf. "Umschau" 1970 p. 652 and P. Schulster in "Die Zeit" of date 4 January 1974. Apparently the phthalimide structure of these fungicides is responsible for the detrimental effects. Of interest in this connection is the fact that the malformation-causing Contergan (thalidomide) (VII) also has the same phthalimide structure. ##STR4##
In developing new fungicides therefore, certain properties are desirable. Thus, a good fungicide should:
(1) have good activity of long duration, PA1 (2) be very soluble in petroleum hydrocarbons; and PA1 (3) be harmless in use.
Since fungicides of the type of N-trichloromethylthiodicarboxylic acid imides have long duration of action, extensive investigations were carried out with an aim to finding fungicides of that type which fulfill these requirements. It was found that of a large number of synthetically prepared compounds, by no means all compounds of general structural formula ##STR5## display fungicidal activity as disclosed in U.S. Pat. No. 2,553,770 notes hereinabove. Rather, activity is associated with strictly defined structural features. Thus, the trichloromethylthio compounds obtained from anthracene-maleic anhydride adduct, caryophyllen-maleic anhydride adduct, isoeugenol-maleic anhydride adduct, homophthalic anhydride, camphoric anhydride, hexadecyl succinic anhydride and many other anhydrides are inactive.